package http

import (
	"context"
	_ "embed"
	"log"
	"meshgo/config"
	"meshgo/stats"
	"net/http"
	"time"

	"github.com/gin-gonic/gin"
)

// Server HTTP 管理界面服务
type Server struct {
	srv     *http.Server
	enabled bool
}

// New 创建 HTTP 服务（不启动）
func New(cfg *config.AdminConfig) *Server {
	if !cfg.Enabled {
		return &Server{enabled: false}
	}

	gin.SetMode(gin.ReleaseMode)
	r := gin.New()
	r.Use(gin.Recovery())

	// 预留认证中间件扩展点
	r.Use(AuthMiddleware(cfg))

	// 路由
	admin := r.Group("/admin/mqtt")
	{
		admin.GET("/api/stats", handleStats)
		admin.GET("/api/clients", handleClients)
		admin.GET("/api/client/:id", handleClientDetail)
		admin.GET("/api/client/:id/subs", handleClientSubs)
	}
	r.GET("/admin/mqtt", serveAdmin)
	r.GET("/admin/mqtt/client/:id", serveClientDetail)
	r.GET("/", serveIndex)

	// Meshtastic 消息查看
	meshtastic := r.Group("/admin/meshtastic")
	{
		meshtastic.GET("/", serveMeshtastic)
		meshtastic.GET("/api/messages", handleMessages)
	}

	addr := cfg.Port
	if addr == "" {
		addr = ":8080"
	}

	return &Server{
		enabled: true,
		srv: &http.Server{
			Addr:         addr,
			Handler:      r,
			ReadTimeout:  10 * time.Second,
			WriteTimeout: 10 * time.Second,
		},
	}
}

// Start 启动 HTTP 服务（goroutine）
func (s *Server) Start() {
	if !s.enabled {
		return
	}
	go func() {
		addr := s.srv.Addr
		log.Printf("[http] 管理界面已启动: http://%s/", addr)
		if err := s.srv.ListenAndServe(); err != nil && err != http.ErrServerClosed {
			log.Printf("[http] 管理界面启动失败: %v", err)
		}
	}()
}

// Close 优雅关闭
func (s *Server) Close() error {
	if !s.enabled {
		return nil
	}
	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
	defer cancel()
	return s.srv.Shutdown(ctx)
}

// Enabled 返回是否启用
func (s *Server) Enabled() bool { return s.enabled }

// ---------------------------------------------------------------------------
// 路由处理
// ---------------------------------------------------------------------------

// serveIndex 返回管理页面
func serveIndex(c *gin.Context) {
	c.Header("Content-Type", "text/html; charset=utf-8")
	c.String(http.StatusOK, homeHTML)
}

// serveAdmin MQTT 管理页面
func serveAdmin(c *gin.Context) {
	c.Header("Content-Type", "text/html; charset=utf-8")
	c.String(http.StatusOK, adminHTML)
}

// serveClientDetail 客户端详情页面
func serveClientDetail(c *gin.Context) {
	c.Header("Content-Type", "text/html; charset=utf-8")
	c.String(http.StatusOK, clientDetailHTML)
}

// serveMeshtastic Meshtastic 消息查看页面
func serveMeshtastic(c *gin.Context) {
	c.Header("Content-Type", "text/html; charset=utf-8")
	c.String(http.StatusOK, meshtasticHTML)
}

// handleMessages 返回 msh 消息列表（JSON）
func handleMessages(c *gin.Context) {
	messages := stats.GetMessages()
	pskIndex := stats.GetDefaultPSKIndex()

	for i := range messages {
		if isJsonTopic(messages[i].Topic) {
			continue
		}

		dec, err := stats.TryDecryptMessage(messages[i].Payload, pskIndex)
		if err != nil {
			// 打印详细错误
			env, parseErr := stats.ParseServiceEnvelopeDebug(messages[i].Payload)
			if parseErr != nil {
				log.Printf("[decrypt] FAIL psk=%d topic=%s parse_err=%v decrypt_err=%v payload_len=%d",
					pskIndex, messages[i].Topic, parseErr, err, len(messages[i].Payload))
			} else {
				packetId := uint64(0)
				from := uint32(0)
				variant := 0
				encryptedLen := 0
				if env.Packet != nil {
					packetId = env.Packet.Id
					from = env.Packet.From
					variant = env.Packet.WhichPayloadVariant
					encryptedLen = len(env.Packet.Encrypted)
				}
				log.Printf("[decrypt] FAIL psk=%d topic=%s channel=%s packetId=%d from=0x%x variant=%d encrypted_len=%d err=%v",
					pskIndex, messages[i].Topic, env.ChannelId, packetId, from, variant, encryptedLen, err)
			}
			messages[i].Decrypted = &stats.DecryptedMessage{
				GatewayId: err.Error(),
			}
		} else if dec != nil {
			messages[i].Decrypted = dec
			log.Printf("[decrypt] OK topic=%s channel=%s packetId=%d from=0x%x port=%d payload_len=%d",
				messages[i].Topic, dec.ChannelId, dec.PacketId, dec.From, dec.PortNum, len(dec.Payload))
		}
	}

	c.JSON(http.StatusOK, gin.H{
		"code": 0,
		"data": messages,
	})
}

func isJsonTopic(topic string) bool {
	return len(topic) > 0 && (topic[len(topic)-1] == 'n' || topic[len(topic)-5:len(topic)] == "/json")
}

// handleStats 返回实时统计（JSON）
func handleStats(c *gin.Context) {
	c.JSON(http.StatusOK, gin.H{
		"code": 0,
		"data": stats.GetStats(),
	})
}

// handleClients 返回在线客户端列表（JSON）
func handleClients(c *gin.Context) {
	st := stats.GetStats()
	c.JSON(http.StatusOK, gin.H{
		"code": 0,
		"data": st.Clients,
	})
}

// handleClientDetail 返回指定客户端详情（JSON）
func handleClientDetail(c *gin.Context) {
	id := c.Param("id")
	info := stats.GetClient(id)
	if info == nil {
		c.JSON(http.StatusOK, gin.H{
			"code": 404,
			"msg":  "客户端不存在或已离线",
		})
		return
	}
	c.JSON(http.StatusOK, gin.H{
		"code": 0,
		"data": info,
	})
}

// handleClientSubs 返回指定客户端的订阅主题列表（JSON）
func handleClientSubs(c *gin.Context) {
	id := c.Param("id")
	subs := stats.GetClientSubs(id)
	c.JSON(http.StatusOK, gin.H{
		"code": 0,
		"data": subs,
	})
}

// ---------------------------------------------------------------------------
// 认证中间件（预留扩展点）
// AuthMiddleware 根据 cfg.AuthType 选择对应认证策略
// 当前支持：none
// 预留支持：basic、token
// ---------------------------------------------------------------------------

// AuthMiddleware 认证中间件工厂
func AuthMiddleware(cfg *config.AdminConfig) gin.HandlerFunc {
	switch cfg.AuthType {
	case "basic":
		return basicAuth(cfg.Username, cfg.Password)
	case "token":
		// TODO: token 认证
		return func(c *gin.Context) { c.Next() }
	default:
		// none：不做认证
		return func(c *gin.Context) { c.Next() }
	}
}

// basicAuth Basic 认证
func basicAuth(user, pass string) gin.HandlerFunc {
	return func(c *gin.Context) {
		u, p, ok := c.Request.BasicAuth()
		if !ok || u != user || p != pass {
			c.Header("WWW-Authenticate", `Basic realm="meshgo"`)
			c.AbortWithStatusJSON(http.StatusUnauthorized, gin.H{
				"code": 401,
				"msg":  "未授权",
			})
			return
		}
		c.Next()
	}
}

// ---------------------------------------------------------------------------
// 模板（go:embed 内嵌）
// ---------------------------------------------------------------------------

//go:embed index.html
var homeHTML string

//go:embed admin_mqtt.html
var adminHTML string

//go:embed client_detail.html
var clientDetailHTML string

//go:embed meshtastic.html
var meshtasticHTML string